The previous qemu virt-machine smmuv3 model and the new arm-smmuv3 model cannot both be specified at the same time. When launching a Libvirt VM with a single arm-smmuv3 model denoted by the <pciBus> attribute, qemuBuildMachineCommandLine() still appends the iommu=smmuv3 -machine parameter in addition to the arm-smmuv3 model passed to -device, preventing the VM from booting. Use the presence of a non-negative pci_bus to identify the multi-smmuv3 IOMMU model, instead of the niommus attribute. This allows for specifying a single arm-smmuv3 on the qemu command line, instead of both the virt-machine smmuv3 and arm-smmuv3 being specified at the same time. This patch is available on Github [0]. [0] https://github.com/NathanChenNVIDIA/libvirt/commits/single-smmuv3-12-25/ Signed-off-by: Nathan Chen <nathanc@nvidia.com> Nathan Chen (1): qemu: Use pci_bus to identify multi-smmuv3 model src/qemu/qemu_command.c | 2 +- src/qemu/qemu_postparse.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) -- 2.43.0